LMT AMI Caused by a Valve-Like Ridge in a 9-Year-Old Boy Successfully Treated With PCI

A 9-year-old boy was suspected of having acute myocardial infarction and emergency coronary angiogram was performed. No signs of flow limitation in either coronary artery was detected. We performed intravascular ultrasonography from the ascending aorta, which showed a ridge on the left main trunk acting like a valve, resulting in significant stenosis. Percutaneous coronary intervention with stent deployment was performed with good result.

ongoing chest pain.Electrocardiography revealed STsegment elevation in augmented vector of the right arm and ST-segment depression in precordial leads suggestive of left main trunk (LMT) acute myocardial infarction (Figure 1), and emergency coronary angiography (CAG) was performed.

MEDICAL HISTORY
The patient had a history of bronchial asthma, and no asthma attacks were detected for years, and had not taken any medication.

DIFFERENTIAL DIAGNOSIS
A possible cause of chest pain and electrocardiography findings are takotsubo cardiomyopathy and acute myocarditis with pericarditis, but, because Acute Coronary Syndrome is an emergent condition, CAG had to be performed immediately.

LEARNING OBJECTIVES
To understand the pathophysiology of acute coronary syndrome caused by valve-like ridge ostium of LMT using intravascular imaging.
To understand that there is a possibility of overlooking stenosis in coronary ostium when engaging a catheter into the coronary, whereas nonselective left coronary sinus angiography may have chance of clarifying the underlying disease.
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DISCUSSION
There are several reports of a valve-like ridge on the ostium of the LMT resulting in ischemia and sudden death, but this appears to be the first report of successful treatment with PCI.The condition has poor prognosis, perhaps due to difficulty in diagnosis because a standard angiogram may not reveal the ridge when the catheter pushes it against the coronary wall (Figure 4).In this case, the flap created by the ridge was identified with a nonselective left coronary sinus angiography and intravascular ultrasonography from the aorta.We suppose that the nonselective left coronary sinus angiography is useful method, when usual coronary angiography by engaging catheter into coronary artery could not identify the culprit lesion, in case of AMI caused by valve-like ridge ostium.The stent covering the ridge performed ideally, both short-and long-term.Valve-Like Ridge Ostium as Cause of LMT AMI J U L Y 1 7 , 2 0 2 4 : 1 0 2 4 0 4 ( h t t p : / / c r e a t i v e c o m m o n s .o r g / l i c e n s e s / b y / 4 .0 / ) .INVESTIGATIONS CAG revealed several collateral arteries extended from the right coronary artery to the left anterior descending artery, but there were no signs of flow limitation in either coronary artery (Video 1).The patient was transferred to cardiac intensive care.The next day, when chest pain recurred with cold sweats and increases in levels of creatinine kinase (4559) and creatinine kinasemyocardial band (382), emergency CAG was performed again, achieving the same results as the initial procedure.Nonselective left coronary sinus angiography revealed a slit at the ostium of the LMT, suggesting severe stenosis (Figure 2A), and percutaneous coronary intervention (PCI) was performed.MANAGEMENT Intravascular ultrasonography from the ascending aorta showed a ridge on the LMT acting like a valve, resulting in significant stenosis (Figures 2B to 2G).